Question

How do you simplify `(9-5i)(7+4i)`?

Answer 1

Solve as normal, then replace the `i`s

Explanation:

Foil
`=63+36i-35i-20i^2`

Combine Like Terms
`=63+i-20i^2`

Substitute in `i^2 = -1`
`=63+i+20`

Add Numbers
`83+i`